Entity Framework 6 - Consultas de tempo

public class EFLoggerForTesting : IDbCommandInterceptor
{
    static readonly ConcurrentDictionary<DbCommand, DateTime> m_StartTime = new ConcurrentDictionary<DbCommand, DateTime>();

    public void ReaderExecuted(DbCommand command, DbCommandInterceptionContext<DbDataReader> interceptionContext)
    {
        Log(command, interceptionContext);
    }

    public void NonQueryExecuted(DbCommand command, DbCommandInterceptionContext<int> interceptionContext)
    {
        Log(command, interceptionContext);
    }

    public void ScalarExecuted(DbCommand command, DbCommandInterceptionContext<object> interceptionContext)
    {
        Log(command, interceptionContext);
    }

    private static void Log<T>(DbCommand command, DbCommandInterceptionContext<T> interceptionContext)
    {
        DateTime startTime;
        TimeSpan duration;


        if (m_StartTime.TryRemove(command, out startTime))
        {
            duration = DateTime.Now - startTime;
        }
        else
            duration = TimeSpan.Zero;

        var requestId =-1;
        string message;

        var parameters = new StringBuilder();
        foreach (DbParameter param in command.Parameters)
        {
            parameters.AppendLine(param.ParameterName + " " + param.DbType + " = " + param.Value);
        }

        if (interceptionContext.Exception == null)
        {
            message = string.Format("Database call took {0} sec. RequestId {1} \r\nCommand:\r\n{2}", duration.TotalSeconds.ToString("N3"), requestId, parameters.ToString() + command.CommandText);
        }
        else
        {
            message = string.Format("EF Database call failed after {0} sec. RequestId {1} \r\nCommand:\r\n{2}\r\nError:{3} ", duration.TotalSeconds.ToString("N3"), requestId, parameters.ToString() + command.CommandText, interceptionContext.Exception);
        }

        Debug.WriteLine(message);
    }


    public void NonQueryExecuting(DbCommand command, DbCommandInterceptionContext<int> interceptionContext)
    {
        OnStart(command);
    }

    public void ReaderExecuting(DbCommand command, DbCommandInterceptionContext<DbDataReader> interceptionContext)
    {
        OnStart(command);
    }

    public void ScalarExecuting(DbCommand command, DbCommandInterceptionContext<object> interceptionContext)
    {
        OnStart(command);
    }
    private static void OnStart(DbCommand command)
    {
        m_StartTime.TryAdd(command, DateTime.Now);
    }
}